How to Make It
Combine Castelvetrano olives, Peppadew peppers, Kalamata olives, red wine vinegar, and lemon peel strips in a medium bowl.
Heat olive oil and anchovy fillets in a saucepan over medium-low. Cook, stirring often, until anchovies dissolve, 5 minutes. Add smashed garlic cloves, rosemary sprigs, and fennel seeds. Cook, stirring constantly, until fragrant, about 30 seconds. Pour hot oil mixture over olive mixture; stir to combine.
Cover; chill at least 24 hours or up to 1 week. Let stand at room temperature 1 hour before serving.